The article compares simulated and empirical experiments and shows that simulations have strengths that empirical methods lack, but they also have important relative weaknesses. The authors identify three threats to internal validity and two forms of external validity peculiar to simulated experiments. The article also looks at the problem of validating simulations with crime data and suggests that simulations need to mimic the error production processes involved in the creation of empirical data. This work argues that simulated experiments of crime prevention interventions are an important class of research methods that compare favorably with empirical experiments. It draws on previous work from Popper’s “demarcation between science and nonscience” and Epstein’s “principle of generative explanation” to show how simulated experiments can falsify theory. It concludes by listing ways simulations can be used to improve empirical experiments, seven specific means are cited, some which tighten the conceptualization of theories, others which assist in the planning of experiments and others which aid in the analysis and interpretation of results. Additional discussion concerning the differing operating assumption of empirical and simulation experimentalists is offered. Tables, figure, references